This involves updating the bootstrap code since it needs a fix in
interface resolution. It shouldn't affect the Idris2-boot build though,
since it's in the libraries not the Idris2 source.
It's worth delaying in case doing some more work (and some more
interface resolution) can make the type more concrete. This makes
test linear011 work more smoothly, and will help with this sort of
program in general.
A better way, later, would be to try elaborating and delay only if the
type is not yet known. We have the facilities, but it's too fiddly for
me to want to implement it right now...
We need to check below top level too, since there could be holes that
we're happy to resolve by searching. The linearity test added
illustrates a place where this is needed.
Doing this is awkward, for a number of reasons, including 'pure' not
being linear in its argument - there's no guarantee it'll be used
linearly after all - and lack of multiplicity polymorphism. Fortunately
the user doesn't have to know about the ugliness underneath!
We can look at ways to make it less horrible later :). For now, this is
starting to look like something that allows us to write linear protocols
without too much extra machinery on top of IO.
It's okay to use locals once we've applied the default hint itself -
it's just committing to locals too early we want to avoid. This allows
%defaulthint to be more expressive (under the assumption we want it to
be :). But shortly we will need it...)
Conditional variables with timeout in Chez didn't work, so changed to a
consistent meaning of the timeout (microseconds). Also fix linearity of
unsafePerformIO.
The namespace parser was not requiring a minimum indentation and instead
based its indentation on the following line, which meant that a line like:
namespace Foo
foodef : Int
placed foodef into namespace Foo instead of the module's top level.
And so made it unclear when a namespace ends.
Following a fairly detailed discussion on slack, the feeling is
generally that it's better to have a single interface. While precision
is nice, it doesn't appear to buy us anything here. If that turns out to
be wrong, or limiting somehow, we can revisit it later. Also:
- it's easier for backend authors if the type of IO operations is
slightly less restrictive. For example, if it's in HasIO, that limits
alternative implementations, which might be awkward for some
alternative back ends.
- it's one less extra detail to learn. This is minor, but there needs to
be a clear advantage if there's more detail to learn.
- It is difficult to think of an underlying type that can't have a Monad
instance (I have personally never encountered one - if they turns out
to exist, again, we can revisit!)
This addresses the case where you'd see an error of:
Ambiguous elaboration at:
r <- pure []
Possible correct results:
[]
[]
[]
By changing it to:
Possible correct results:
Main.Nil
PrimIO.Nil
Prelude.Nil
